无法获得多对多关系，但附加/分离在Laravel 5.2中正常工作

Question

完整错误是：

1066 Not unique table/alias: 
SQL: select `salons_services_salons_services_sex`.*,
    `salons_services_salons_services_sex`.`salons_services_id` as `pivot_salons_services_id`,
    `salons_services_salons_services_sex`.`salons_services_sex_id` as `pivot_salons_services_sex_id`
from `salons_services_salons_services_sex`
    inner join `salons_services_salons_services_sex` on `salons_services_salons_services_sex`.`id` = `salons_services_salons_services_sex`.`salons_services_sex_id`
where `salons_services_salons_services_sex`.`salons_services_id` = 92

型号：

class SalonService extends Model
{

    public function sex() {
        return $this->belongsToMany('App\Models\SalonServiceSex',
            'salons_services_salons_services_sex',
            'salons_services_id',
            'salons_services_sex_id')
        ;
    }
}

尝试使用$ service-＆gt;获取相关记录会导致错误，但attach（）或detach（）正常工作，因此我可以使用此方法链接模型。

修改 将生成的查询更新为

select `salons_services_salons_services_sex`.*,
  `salons_services_salons_services_sex`.`salons_services_id` as `pivot_salons_services_id`,
  `salons_services_salons_services_sex`.`salons_services_sex_id` as `pivot_salons_services_sex_id`
  from `salons_services_salons_services_sex`
    inner join `salons_services_sex` as s1
      on s1.`id` = `salons_services_salons_services_sex`.`salons_services_sex_id`
  where `salons_services_salons_services_sex`.`salons_services_id` = 93

并且工作正常

获取相关记录：

$service->sex;

表：

salons_services:
id
name
time

salons_services_salons_services_sex:
salons_services_id
salons_services_sex_id

salons_services_sex:
id
name